In NM imaging, radiopharmaceuticals are injected into a person and then detectors (e.g., gamma cameras), typically mounted on a gantry, capture and form images from the radiation emitted by the radiopharmaceuticals. The NM images primarily show physiological function of, for example, a patient or a portion of a patient being imaged.
Collimation may be used to create an image of radiation-emitting objects in the field of view of the detectors. Different types of collimation are known, for example, different shapes and configurations of collimators are known for use in different types of applications. However, when designing collimators a tradeoff exists between resolution and sensitivity. For example, a high-resolution collimator views a very narrow column of activity from the patient, and therefore provides high spatial resolution, but at a reduced sensitivity. In contrast, a high sensitivity collimator accepts radiation from a wider range of angles, which increases the sensitivity, but reduces resolution. Thus, depending on desired or required imaging characteristics or properties, collimators are designed to provide resolution and sensitivity levels to maximize or optimize imaging based on the desired or required characteristics or properties. However, such designs may perform unsatisfactorily in different applications.
As one example, in pinhole collimators, such as for Single Photon Emission Computed Tomography (SPECT) imaging detectors, the field of view of the detector depends on the size of the detector and the focal length of the collimator. Thus, there is a tradeoff between field of view, resolution, sensitivity, and detector area.
Accordingly, known collimator designs often require one or more compromises. Thus, these designs may result in detectors that have less than optimal imaging for a particular application.